A monitoring for susceptibility to imidacloprid in the larger house fly Musca domestica (Diptera: Muscidae) was initiated in the laboratory. This stewardship program includes baseline susceptibility studies, monitoring of fly populations and the evaluation of biochemical mechanisms of insecticide resistance in Musca domestica. Imidacloprid is characterized in fly bait formulations by a fast knock down, high attractiveness, and residual efficacy over a period of several weeks which was confirmed under field conditions in livestock facilities and urban areas.